Valley Briefing

They're Back : Santa Anas Blow Back Into Town

The Santa Ana winds are on their way, and with them comes the reminder of the wildfires last fall that claimed 1,241 structures, almost 200,000 acres and $1 billion in damages. Three people, each from Topanga Canyon, lost their lives.

Santa Ana season runs from late summer to autumn, but sometimes extends into winter, knocking out power, tripping burglar alarms and whipping up other bits of mischief as desert winds blow.

The phenomenon originates hundreds of miles from Southern California in a high-pressure system over Utah. Although the topography and position of the San Fernando Valley put it in the route of the hot, dry winds that blow in from the desert--the Valley has had gusts of up to 60 m.p.h.--the condition is generally strongest in the Riverside-San Bernardino area.

The Santa Ana's aren't all bad. In addition to granting warm weather, they also blow the San Fernando Valley's pollutants out of our area. But they also carry mysteries in from the east. Wrote Joan Didion: "It is the season of suicide and divorce and prickly dread, whenever the wind blows."

Tracing the Name

There are many theories, some legendary, as to why the winds are called Santa Anas. Some believe the name comes from the Satanas, Spanish for Satan. But most likely they are named for the Santa Ana Canyon, the narrow gap in the Santa Ana Mountains in Orange and Riverside counties, where the winds are especially strong.

Contributing Factors

Dry cold fronts passing through the Great Basin states are followed by a high-pressure system that is centered over the Utah-Nevada border, creating westerly winds that eventually become Santa Anas.

Flowing from Desert to Valley

Santa Ana winds move through the San Gabriel Mountains and approach the Valley from the north-northeast, funneling through the Soledad Canyon and Weldon Canyon area into the Valley. The heat of the wind is more the result of its downhill motion than its movement across the desert. This is their path:

1. Air is cool and holds fair amount of moisture

2. Air loses moisture as it moves up mountains

3. Wind speed increases as air funnels through mountain passes

4. Temperature of the air increases 5.5 degrees for every 1,000 feet it descends

5. Air that passes over and through mountains has lost almost all moisture

Comparing gusts

Santa Ana gusts have been recorded up to 60 m.p.h. Here is how other weather systems' winds compare:

Sandstorm: 30 m.p.h. or more

Dust storm: 30 m.p.h. or more

Tropical depression: 38 m.p.h. or less

Tropical storm: 39-78 m.p.h.

Gale: 39-54 m.p.h.

Severe blizzard: 45 m.p.h. or more

Hurricane: 74 m.p.h. or more

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"There was a desert wind blowing that night. It was one of those hot, dry Santa Anas that come down through the mountain passes and curl your hair and make your nerves jump and your skin itch. On nights like that, every booze party ends in a fight, meek little wives feel the edge of the carving knife and study their husbands' necks. Anything can happen."